In view of the abnormal vibration occurred during the operation of a synthetic gas compressor unit in a coal methanol plant, the conventional vibration factors such as mechanical failure were removed, the process and operation condition including gas composition and reaction condition etc. were analyzed. It is put forward that through adjusting the content of purified gas component, the reasonable ratio of H2, CO and CO2, and keeping the methanol synthesis reaction rate basically stable, so that the pressure and flow of the compressor system are relatively stable in a certain range, so that the abnormal vibration of methanol synthesis gas compressor is disappeared, and the normal operation condition is restored.